The fractionation of serum GGT by high‐performance gel filtration liquid chromatography can be used for the differential diagnosis of alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD), in which the alcohol metabolite acetaldehyde induces an increase in the expression of GGT, with the highest s‐GGT/t‐GGT ratio and the lowest f‐GGT/t‐GGT ratio in alcoholic liver disease (ALD) [153]. This evidence concerns the gene GGT1 and metabolic dysfunction-associated steatotic liver disease.